1. Field of Invention
The present invention relates to a glass flake based hybrid hermetic sealing system useful in solar cells based on silicon, organic systems, and thin layer solar cells as well as other electronic devices such as organic LEDs (OLED).
2. Description of Related Art
Conventional formation of hermetic seals of electronic devices such as thin layer solar cells or OLEDs involves the application of organic pastes or tapes at the edges of the device followed by a thermal, ultraviolet light or chemically induced curing cycles. The organic sealants are not truly hermetic and sometimes contain getters to mitigate their non-hermeticity. Truly hermetic seals can be made from glass based systems by printing and firing a paste composition including a glass frit and organic solvent/binder system. Drawbacks of such systems include the need to fire at extremely high temperatures, e.g., 800° C., and the problem of entrapment of organic residue and incomplete burnout of the binder system (such as ethyl cellulose) within the hermetic seal. Such entrapment causes undesired contamination of active layers sealed, such as solar cells or OLEDs, within the hermetic seal.
Accordingly, improvements in the art of hermetic sealing are required.
Hybrid inorganic platelet filler organic matrix systems have been utilized to produce improved gas barrier layers primarily in the food packaging industry. Examples include U.S. Pat. No. 4,618,528 in which the platelet filler is preferentially talc, U.S. Pat. No. 4,818,782 in which the platelet filler is mica and U.S. 2011/0081534 in which the platelet filler is glass flakes.